Geekvape Z coils, what the XM Boost generation changed
Two boxes of Geekvape Z coil heads can carry the same value, 0.15 ohm, and still list different wattage ranges. One says 80 to 90 W, the other 70 to 85 W. That is not a retailer typo but the mark of a generation change in a coil family that serves the whole Zeus line. Before touching the mod, the lab cross-checked the listings to work out which head is actually in your hand.
Which Geekvape Z coil for which setting
The Geekvape Z coil range comes in four Kanthal A1 mesh values, all designed for direct lung vaping and usually sold in packs of five. The retailers consulted publish the same ranges for the XM Boost version, the most recent one.
| Value | Generation | Listed range | Current at either end of the range |
|---|---|---|---|
| 0.15 ohm | XM Boost | 70 to 85 W | 21.6 to 23.8 A |
| 0.2 ohm | XM Boost | 70 to 80 W | 18.7 to 20 A |
| 0.25 ohm | Dual mesh | 45 to 57 W | 13.4 to 15.1 A |
| 0.4 ohm | XM Boost | 50 to 60 W | 11.2 to 12.2 A |
| 0.15 ohm | Original Z | 80 to 90 W | 23.1 to 24.5 A |
The last row only concerns older stock still in circulation. For a first setting, the lab starts at the bottom of the chosen value’s range, then climbs in steps of 2 or 3 W for as long as the flavour stays clean.
Z, Z XM and XM Boost, three generations behind one letter
The Z family first existed as a plain version, then as an XM version, before the XM Boost arrived. Two retailers explicitly present this latest generation as the replacement for the original Z heads, which is why mixed boxes still turn up in some stock.
On the 0.2 and 0.4 ohm, moving from one generation to the next leaves the published figures untouched, at 70 to 80 W and 50 to 60 W. The whole difference sits in the 0.15 ohm. The original Z was rated at 80 to 90 W, whereas the XM Boost is rated at 70 to 85 W.
In practice, the floor drops by 10 W and the ceiling by 5 W, so the range widens from 10 to 15 W. A mod set at 88 W for an old 0.15 ohm therefore sits above what the listings give for the new one. Switching generation without adjusting the power pushes the head beyond its published range.
The useful clue is printed on the packaging. An XM or XM Boost marking means the recent generation, its absence an original Z, and the range to apply follows from that.
Same power, two different currents
The ranges of the 0.15 and 0.2 ohm XM Boost overlap between 70 and 80 W, and none of the listings consulted explains what separates them in that shared zone. Ohm’s law gives a numerical answer, since current equals the square root of power divided by resistance.
At 75 W, in the middle of the shared zone, the 0.15 ohm carries about 22.4 A at 3.35 V. The 0.2 ohm, set identically, stays at 19.4 A at 3.87 V. For the same power on the screen, the lower value asks the mod for roughly 15% more current.
That extra current brings no extra heat, since the power is identical. It does, however, put more load on the electronics and the cells, which matters on a single-battery mod. Our breakdown of GTi coils shows how to get from this figure to the current drawn from the battery, and the same calculation applies to the Z family.
At the other end of the range, the 0.4 ohm tops out at 12.2 A at 60 W, half of what the 0.15 ohm draws at the top of its range. It is the value that leaves the most headroom on a modest mod.
Which tanks take a Geekvape Z coil
Whether a Geekvape Z coil fits is decided by the tank, not by the name of the kit. The lab only kept the models named by at least two retailers, then isolated the exceptions that can cost a whole pack.
The Z family of tanks
Listings agree on the Zeus Sub Ohm, its 2021 version, the Z Sub Ohm SE and the Z Subohm Tank 5, as well as on the Z Fli and Z Fli 2, the P Sub Ohm and the Obelisk Tank. These lists also include the Aegis Legend 2, Legend 3, Legend 5, Solo 3 and Aegis Touch T200 kits, which ship with one of those tanks.
UK buyers should keep one more point in mind. Refillable tanks sold here are limited to 2 ml, a rule that applies to the tank itself, not to the coil head that sits inside it.
The 0.25 ohm exception
Three retailers repeat it, the 0.25 ohm Z coil in Dual mesh does not fit the P Sub Ohm. All three XM Boost values remain usable in that tank. Several recent listings, a UK one among them, now only describe the 0.15, 0.2 and 0.4 ohm.
Heads that look like a Z without being one
Geekvape sells other series with a similar shape. The B and M series cannot replace a Z head, and the Z Max, despite its name, takes M series heads. Our Geekvape coils bench test covers the B series in detail.
The same confusion crosses brands. Innokin’s Z Coils, an unrelated family, fit the Zenith and the Zlide, as our guide to Innokin coils shows. A shared letter never means compatibility, only the tank’s own list counts.
E-liquid, priming and replacing a Z head
A high-power mesh head soaks up its cotton quickly, and listings agree on three habits that shape how long it lasts.
On e-liquid, retailers recommend a high-VG blend, up to 70% for the lowest values. Two of them advise against 50/50, which can leak through the mesh of these heads. In the UK, nicotine e-liquid comes in bottles of 10 ml at most, capped at 20 mg/ml, and high-VG blends are often sold as nicotine-free shortfills.
Before the first puff, put a few drops of liquid on the exposed cotton, fill the tank and wait 3 to 5 minutes, the time Geekvape gives. Our method to prime a vape coil walks through each step.
A head that gives a lingering burnt taste or noticeably weaker vapour is reaching the end of its life. A very sweet recipe usually gums up the mesh faster than a light fruit liquid.
Which Z value for your mod and your draw
Choosing a Geekvape Z coil comes down to three criteria, the power the mod delivers comfortably, the current it accepts and the tank that will hold the head.
With a mod that tops out around 60 W or a slightly tighter draw, the 0.4 ohm XM Boost is the most coherent value, with the lowest current in the range. Between 70 and 80 W, the lab prefers the 0.2 ohm, which covers the same zone as the 0.15 while asking for about 13% less current.
The 0.15 ohm XM Boost earns its place above 80 W, as the only value rated up to 85 W, on a mod able to push more than 23 A through the coil. A P Sub Ohm owner rules out the 0.25 ohm from the start, and an old original Z 0.15 still in stock is set to its own range, not the XM Boost one.
FAQ
These five questions come up in searches around the Z family. The answers rely on the retailer listings the lab consulted.
Do Z coils fit a Zeus RTA?
No. The Zeus X and the Zeus Dual are rebuildable tanks, flagged by the RTA label. They take a hand-built wire and cotton build, not a ready-made Z series head.
How do you change the coil in a Zeus tank?
Unscrew the tank from the mod, then remove its base. The worn head pulls straight out, because Z heads push-fit without a thread, and the new one pushes in the same way once primed.
Are Geekvape Z coils sold individually?
Most retailers sell them in packs of five heads of the same value. A few shops also sell them one at a time, which lets you try a value before committing to a pack.
Is a Z coil suitable for mouth-to-lung vaping?
No. Every value in the family is described for direct lung vaping, with ranges starting at 45 W. A mouth-to-lung draw calls for higher-resistance heads used at low power.
Do Z coils work with nicotine salts?
The listings consulted do not mention nicotine salts for this family. Those liquids are mostly offered for a tight draw at modest power, a long way from a head rated at 45 to 85 W.
Geekvape Z coil choice, read the generation before the value
On the Z family, the ohm value is not enough. An original 0.15 ohm and an XM Boost 0.15 ohm carry the same number without sharing the same range, and the 0.25 ohm does not follow the others in the P Sub Ohm.
Read through Ohm’s law, the range sorts itself out, from the 0.4 ohm that is light on current to the 0.15 ohm that passes 23 A at the top of its range. Chosen this way, a Geekvape Z coil is a reminder that any tank is first set up with its manual and a calculator, before it is judged on vapour.
Editorial content for adult readers only. Nicotine vaping products are not for sale to anyone under 18 in the UK. Vaping products can contain nicotine, a substance that causes addiction. This article is not a buying recommendation.
